The present invention relates generally to electrochemical systems, and more particularly relates to a removable electrochemical cell assembly and manifold system for receiving and interconnecting the same.
Electrochemical cells, i.e., cells which employ a chemical reaction to develop an electrical potential, are an important aspect of many power delivery applications. In many of these applications, a suitable power source requires the use of multiple cells which are interconnected to provide a suitable output voltage and current capacity. Often, this is achieved by permanently electro-mechanically interconnecting a number of cells in a suitable configuration. Unfortunately, in such a case, when a single cell fails it is difficult to replace the defective cell. As a result, the entire battery must be replaced.
An improved electroconversion cell architecture and chemistries are described in U.S. Pat. No. 5,804,329, which is hereby incorporated by reference. In an embodiment of the electroconversion cell described therein, an anolyte solution is separated from a catholyte solution by a permi-selective membrane. As the cell provides electricity to a load, a chemical conversion takes place in such solutions. To prolong the life of the battery, the solutions can be circulated through the cell, thereby replacing converted electrolyte solution with new electrolyte solution. In such a system, the electrolyte solutions can be perpetually replaced, and the anodes and cathodes in the cell assemblies generally do not degrade, resulting in a long life battery. Nevertheless, the cells can eventually fail for a variety of reasons, including physical damage, leakage, or terminal burnout. Thus, in a multi-cell battery, it would be desirable to be able to quickly replace a failed cell.
An object of the invention is to provide a battery architecture which facilitates the replacement of failed cells.
Accordingly, one aspect of the invention is to provide a removable electrochemical cell system assembly which may be engaged with an electrochemical cell manifold. The removable electrochemical cell assembly includes a cell housing having an interface surface, a first chamber, a second chamber, and at least one mechanical connector whereby the removable electrochemical cell may be engaged with the manifold. In addition, the cell assembly has a central membrane separating the first and second chambers, a pair of inlet and outlet conduits in fluid communication with each chamber and extending from the first chamber through the interface surface of the cell housing. The inlet and outlet conduits have connectors at the interface surface which can provide connection with corresponding conduits upon engagement with a manifold. Further, the cell assembly further includes an electrical conductor in each chamber extending from the chamber through the interface surface and electrically coupled to an electrical conductor to provide electrical connection with the manifold.
Preferably, the fluid, mechanical and electrical connectors of each cell are located on a single interface side of each cell and communicate with corresponding structures on the manifold. Thus, the invention provides that a cell assembly may be engaged in fluid and mechanical communication in a manner which facilitates the replacement of individual cells.
A further embodiment of the removable electrochemical cell assembly according to the invention is the incorporation of check valves with the inlet and outlet conduits of the cell assembly which may be operated to control the flow of a fluid in and out of the cell. The check valves may prevent the spillage of fluid from the cell assembly upon removal of the cell assembly from the manifold. In addition, check valves may be used to prevent the back-flow of fluid into a cell which may result when uneven pressure builds up among cells in the manifold.
A further aspect of the removable electrochemical cell assembly according to the invention is the incorporation of conductive filler material electrically coupled to the electrical conductor in either one or both of the chambers of the cell housing.
Another aspect of the removable electrochemical cell assembly according to the invention is the incorporation of one or more drain conduits in fluid communication with either one or both chambers of the cell housing. The drain conduit extends from a chamber through the interface surface of the cell housing. In addition, each drain conduit can include a check valve to prevent the spillage of fluid from the cell assembly upon removal of the cell assembly from the manifold. Further, each drain conduit can include a connector at the interface surface to provide connection with a corresponding conduit of the manifold. Further, each chamber with a drain conduit can have a purge valve extending from the chamber which may be operated in coordination with the check valve of the drain conduit.
A further aspect of the invention is to provide a removable cell assembly for operation with a manifold, where the removable cell assembly is adapted for use with hydrogen fuel cells. The removable hydrogen cell assembly incorporates a hydrogen fuel cell, which includes a hydrogen gas inlet conduit, an air inlet conduit, a by-product outlet conduit and electrical terminals. The hydrogen gas inlet conduit includes a fluid blocking filter to allow the inflow of hydrogen gas to the hydrogen fuel cell while preventing the entrance of fluid from the fluid conduit. The air inlet conduit includes a valve to allow air to enter the hydrogen fuel cell while preventing hydrogen gas from escaping. In addition, the removable hydrogen cell assembly includes a hydrogen cell fluid conduit which includes a fluid inlet aperture, a fluid outlet aperture, and a hydrogen collection chamber. The hydrogen collection chamber can be connected to the hydrogen gas inlet conduit, thereby allowing any collected hydrogen gas to pass to the hydrogen gas inlet conduit. The by-product outlet conduit of the hydrogen fuel cell includes a check valve and an outlet aperture connected to the hydrogen cell fluid conduit, thereby allowing any fluid by-product which may form in the hydrogen fuel cell to pass into the hydrogen cell fluid conduit while preventing fluid from the fluid conduit from entering the hydrogen fuel cell. The electrical terminals of the hydrogen cell allow the hydrogen fuel cell to be electrically coupled to the manifold upon engagement of the removable hydrogen cell assembly with the manifold.
A further aspect of the invention is to provide an electrochemical cell manifold for operation with a removable cell assembly. The manifold includes a contact surface and source and return fluid conduits supported by the manifold. Each conduit includes at least one fluid connector extending through the contact surface of the manifold to which can be engaged the fluid connectors of corresponding conduits of a removable cell assembly. In addition, the manifold includes electrical conduits supported by the manifold, each electrical conduit having at least one electrical receptor and at least one electrical terminal. The electrical receptors can allow connection with corresponding electrical conductors of a cell assembly upon engagement of the cell assembly with the manifold. The electrical terminals of the manifold can be any suitable electrical interface to allow any voltage potential created by a manifold and cell assembly combination to be applied to an external load. In addition, the manifold can include a mechanical connector to hold the removable cell to the manifold upon engagement of the cell assembly with the manifold.
An aspect of the electrochemical cell manifold according to the invention is the incorporation of one or more fluid drain conduits supported by the manifold. Each fluid drain conduit includes a connector extending through the contact surface which can provide connection with a corresponding drain conduit connector of a cell assembly.
A further aspect of the electrochemical cell manifold according to the invention is the incorporation of a fluid valve for each fluid connector of the manifold. The fluid valve can be operated to control the flow of fluid or to prevent the spillage of any fluid which can be in the manifold upon disengagement of a cell assembly from the manifold.
A further aspect of the electrochemical cell manifold according to the invention is the incorporation of a remote manifold with a remote contact surface connected to the fluid connectors and electrical receptors of the manifold by fluid and electrical extensions, thereby allowing the cell assembly to be engaged with the remote contact surface which can be remote from the contact surface of the manifold. In addition, the remote contact surface can include a remote mechanical connector which can hold the cell assembly to the remote contact surface.
Another aspect of the invention is to provide an electrochemical cell system wherein are combined a manifold and at least one removable electrochemical cell assembly, whose various forms have been described above. In addition to the incorporation of a manifold and one or more electrochemical cell assemblies, the electrochemical cell system includes at least one source fluid reservoir and at least one pump; each reservoir and pump connected to each source conduits supported by the manifold. The pump may control fluid flow from each fluid reservoir to a corresponding source fluid conduit. A second return reservoir can be used to provide fluid flow from a corresponding return fluid conduit to a return reservoir for used fluid. Another aspect of an electrochemical cell system described above is the incorporation of each return reservoir with each drain conduit of the manifold wherein each drain conduit empties into a used fluid reservoir.
Another aspect of the electrochemical cell system described above is the incorporation of one or more removable hydrogen cell assemblies. A removable hydrogen cell assembly can be engaged with the manifold of the system by connecting the fluid inlet aperture of the hydrogen cell assembly to a source fluid connector of the manifold, and by connecting the fluid outlet aperture of the hydrogen cell assembly to the manifold. Further, the electrical terminals of the removable hydrogen cell assembly can be electrically coupled to the electrical conduits of the manifold, and the mechanical connector of the hydrogen cell may be engaged with the mechanical connector of the manifold. Thus, one or more removable hydrogen fuel cell assemblies can be incorporated into a system for removal of any hydrogen gas built up by the processes of any electrochemical cell assemblies engaged with the system.